JPS6391586A - Echo bathometer - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to a surveying sounding machine, etc. as claimed in claim 1.
This invention relates to an echo sounder of the type described in the generic concept described in Section 1.

PRIOR TECHNOLOGY Echo sounders used as nautical sounders or surveying sounders first record the boundary layer between seawater and the seabed, so-called seafloor echoes, without gaps so that the water depth can be determined without any hindrance. I have a problem to solve. Efforts to obtain a gap-free record, however, are faced with the difficulty that the received seafloor echoes are not direct reflections of the transmitted pulses. In the seawater/bottom boundary layer, interferences are formed due to irregularities, and these interferences distort the seafloor echoes relative to the transmitted pulses. Therefore, the envelope of the seafloor echo may exhibit a dip that distorts the rising edge of the seafloor echo and extends the echo in time relative to the transmitted pulse. When a ship is sailing, the echo amplitude fluctuates significantly due to the continuously changing interference structure.

In known echo sounders, the amplification of the echo amplifier is automatically adjusted so that an apparent seawater/seafloor boundary layer echo track can be recorded by a recorder configured as an echo writer. or manually increased so that the amplitude of the seafloor echo is limited.

In this way, it is impossible to record seafloor layers and sedimentation lines (sedimentation lines) using an echo sounder. Seafloor layers and sedimentary lines can be detected by so-called sedimentary echoes. Such sedimentary echoes are generated in the lower boundary layer of the sedimentary or seafloor layer, on the opposite side from the seawater, by the reflection of acoustic pulses that have penetrated into the sedimentary or seafloor layer.

The amplitude of such sedimentary echoes is often much smaller than that of ocean floor echoes. The amplitude of the seafloor echo is determined by the reflection in the seawater/sediment boundary layer, since the attenuation of the sound in the sedimentary layer is significantly greater than that of seawater over the same distance. The energy reflected from the ocean floor not only returns vertically directly from below the echo sounder, but also from the entire directional pattern of the echo sounder, so the seafloor echo is elongated compared to the transmitted pulse. occurs and is located just below the seafloor surface1
one or more deposited layer echoes of one or more deposited layers. Overcontrolling the echo amplifier eliminates these smaller sedimentary echoes in the ocean floor echo.

Furthermore, in such an echo sounder, as is known from Republic Patent No. 1,566,848, which is advantageously used as a fish finder, it is possible to distinguish between fish echoes generated by schools of fish and seafloor echoes. The amplification of the recording amplifier can be switched in at least two stages in order to achieve a 1° amplification switch, thus allowing different echo types to be recorded with different intensities or with different degrees of blackness. is carried out as a function of the instantaneous amplitude of the received echo exceeding a predetermined threshold value. By means of a threshold circuit, a threshold value, which is formed as an average value of the echo amplitude over a number of sounding cycles, is then automatically matched to the intensity of the seafloor echo, so that weak fish echoes are reliably detected. . Echoes with small amplitudes, such as fish echoes, are then written in gray, and echoes with large amplitudes, such as seafloor echoes, are written in black. In some cases, gray and black colors are recorded in reverse.

Problems to be Solved by the Invention BE List of Problems Around the time, the echo sounder of F4 Bopé or Kisho was used to clearly record the echo track of the seawater/seafloor boundary layer without any gaps. The object of the present invention is to improve the method so that it can also record ・ and deposition lines.

Means for Solving the Problem The above-mentioned problem is solved by the structure described in the characteristic part of claim 1 in the echo sounder according to the generic concept of claim 1. .

In the echo sounder of the present invention, the echo front surface (hereinafter referred to as
Due to the large amplitude of the front echo (called a front echo), a negative reference voltage is formed which is amplified by each positive half-wave of the echo voltage.

The amplitude of the echo voltage applied to the recording amplifier is reduced in each case by this reference voltage. Therefore, only voltage values greater than this reference voltage are recorded by the recorder. This condition is satisfied by, at each echo voltage, a first positive half-wave generated by the front echo and often a positive half-wave generated by the deposited echo. It is also satisfied by other positive half-waves in the echo voltage generated. However, 1. The positive half-waves in the echo voltage of the seafloor echo generated by the sedimentary echo are always at the same point in time. The temporal occurrence of positive half-waves in the echo voltage of individual seafloor echoes, which are generated by interference relative to the local position, varies statistically significantly. Sedimentary echoes recorded as discrete points are always recorded as points located at the same location, i.e. at the same depth. (This applies, for example, if a point is written in dark black), and other recorded points are detected as gray expanses.

Advantageous embodiments of the invention are described in the implementation section.

One advantageous embodiment of the invention is set out in claim 3. The additional resistor ensures that the differential element formed by the capacitor, resistor and diode is discharged until the reception of the next seafloor echo.

An advantageous embodiment of the invention is also defined in claim 4. Due to this amplification, when an echo recording device such as a thermoprinter is connected, the recording points formed by the positive voltage peaks of the echo voltage are written in dark black; With the discernment ability of the naked eye, successive echo tracks of deposited echoes can be easily detected.

An advantageous embodiment of the invention is also defined in claim 5. This embodiment is advantageous when using echo-writing recording devices or thermal printers that can record in at least two gray levels or degrees of blackness. The third diode supplies the natural form of the echo voltage occurring at the output of the envelope rectifier directly to the output of the first diode which is downstream of the recording amplifier. Here, the echo voltage of the edge echo, amplified by a factor of 50, is added to this initial echo voltage, so that the initial echo voltage always has a steep rising edge.

Effects of the Invention The present invention has the advantage that echoes from the seawater/bottom boundary layer can be clearly displayed without gaps, and the bottom layer and sedimentation line can still be recorded.

Example Next, the present invention will be explained based on an example using figures.

The circuit diagram shown in Figure 1 is the receiving section 1 of the echo sounder.
It shows 0. A description of the known transmitting part, including the transmitting pulse generator and the transmitting transducer, is omitted since it is not important for Kikiri m''JJ.

The receiving part 10 comprises an acoustic transducer with a directional characteristic that makes it possible to rectify and receive the echoes generated by the transmitted pulses, a preamplifier or echo amplifier 12 and a recording amplifier configured as an operational amplifier 13. H. Recording amplifier 13 via first diode 19
A recorder 14 in the form of a thermal printer or recorder is provided, which is connected to the printer. The structure and function of the thermal recorder are described, for example, in German Patent Application No. 3112.
It is described in Publication No. 871.

The acoustic transducer 11, echo amplifier 12, operational amplifier 13, and thermal recorder 14 are connected in series.

A rectifier circuit, hereinafter referred to as a threshold circuit 15, is inserted and connected between the echo amplifier 12 and the operational amplifier 13. The threshold value circuit 15 forms a threshold value in the form of a reference voltage for the operational amplifier 13, which is matched to the front echo wave of the ocean floor waves received in each case.

Threshold circuit 15. is the envelope rectifier 16 (envelope rectifier 1
6, the input side of which is connected to the output side of the echo amplifier 12), a differentiating element connecting the output side of the envelope rectifier 16 with the non-inverting input side of the operational amplifier 13 (this differentiating element consists of a capacitor 1117, A first resistor 18 and a second diode 20 are connected in parallel with the non-inverting input side of the operational amplifier 13.
and a series connection consisting of and). A second resistor 21 is connected in parallel to this series connection. The resistance value of the second resistor 21 is significantly larger than the resistance value of the first resistance value 18. The operational amplifier 13 has a 50-fold amplifier, and its output side is connected to the input side of the thermal recorder 14 through a series connection consisting of the third resistor 22 and the diode 19 described above. The output side of the diode 19 is connected to the ground potential via a fourth resistor 23.

As described in DE 31 12 871 A1, the use of a thermal recorder 14 capable of recording at least two gray levels or degrees of black allows the output side of the envelope rectifier 16 to be diode 2
It has the advantage that the output side of the first diode 19 can be connected directly to the input side of the thermal recorder 14 via the diode 4.

The echo sounder described above operates as follows.

By means of a transmitting transducer (not shown): 1. Acoustic pulses with transmission duration τ are transmitted vertically towards the ocean floor. One transmit pulse is shown schematically in FIG. Echoes generated by reflection from the surface of the ocean floor or underground are received by an acoustic transducer, 11, converted to voltage, and amplified by an unrestricted echo amplifier, 12. At the output of the echo amplifier 12, an echo voltage is generated as shown schematically in FIG.

As mentioned in the introduction, the seafloor echo is elongated compared to the transmitted pulse because the acoustic energy returns vertically from the seafloor directly below the acoustic transducer 11, rather than coming directly from the seafloor below the acoustic transducer 11. Because it comes back from all areas.

This seafloor echo initially shows a pronounced echo front, the so-called front surface, generated by the reflection of acoustic pulses in the seawater/bottom boundary layer. Subsequently,
The part where the envelope of the ocean floor echo is torn apart by interference is shown. Finally, sediment layer echoes are also buried within the seafloor echoes. Sedimentary layer echoes have significantly smaller amplitudes and occur later in time than front echoes in the sedimentary layer due to greater attenuation, because the sedimentary layer lies below the surface of the ocean floor. In other words, it is located after the seawater/bottom boundary layer in terms of time.

After passing through the envelope rectifier 16, the echo voltage of the seafloor echo has a change as shown in FIG. The positive half-wave a represents the front echo generated in the seawater/bottom boundary layer, and the half-wave e represents the sedimentary echo generated by the sedimentary boundary layer located below the seafloor surface. and d and f result from the dip in the envelope of the seafloor echo caused by interference. The echo voltage located at the connection point 4 at the output of the envelope rectifier 16 is differentiated via a capacitor 17 and a resistor 18 of low resistance. Since the diode 20 is connected in series with the resistor 18, a negative voltage is generated at the connection point 5, that is, the non-inverting input side of the operational amplifier 13, as soon as the positive half wave a of the echo voltage passes through the capacitor 1T. . This negative direction voltage decreases with a time constant determined by the capacitance of the capacitor 17 and the resistance value of the resistor 21. However, each sufficiently large positive half-wave following half-wave a of the echo voltage increases the negative direction voltage at node 5.

At the non-inverting input of the operational amplifier 13, a voltage change occurs as shown schematically in FIG.

Only the relatively large half-wave peaks can protrude into the region of positive voltage and thus generate an output signal taken from the operational amplifier 13 that can be passed through the first diode 19.

The signal voltage at the output of diode 19, ie at node 6, is shown schematically in FIG. The writing pulses generated by the positive half-waves a and b and e and f are fed to the thermal recorder 14 to generate the respective sounding point. If the incoming write pulse represents a constant water depth and sediment layer depth, the tops of half-waves a and b are always located at the same position in time (however, due to the action of interference structures, the tops of half-waves a and c and (The position, magnitude, and frequency of the tops of pulses d and f vary strongly). Therefore, in the thermal recorder 14, one continuous track is generated by write pulses a and e, respectively, and write pulses b and f (
An irregular set of points is written because the positions of C and sumo vary statistically depending on the case. The first half-wave a generated by the front echo is recorded without gaps. Since the amplitude of the half-wave e of the echo voltage varies significantly from one seafloor echo to another, in some of the sedimentary echoes, the half-wave enters into the positive voltage region and generates a write pulse. not big enough. However, since all these half-waves generated by the deposition echo in this echo voltage are always located at the same point in time - and so that the sounding points are always represented by approximately the same water depth - these The ability of the naked eye to identify dotted black areas formed on the recording paper by the write pulses as echo tracks is sufficient. The naked eye can then easily observe all the voltage peaks that enter the positive range at the connection point 5 of the circuit, since they are amplified by a factor of 50 and are therefore printed in dark black by the thermal recorder 14. These dark black dots concentrated along one line on the printing paper of the thermal recorder 14 in accordance with the depth of the deposited layer are observed by the naked eye as clear echo tracks, and although they are dark black, their positions vary. The points generated by C, d and f are gray expanses.

observed as.

The third diode is arranged so that the thermal recorder, 14, records the front echo and the sedimentary echo in the ocean floor echo in various gray shades or degrees of blackness, and for this purpose records the writing pulse generated by the front echo and the sedimentary echo. a or e
is to be applied to the thermal recorder 140 input with varying intensities. At the connection point 6, the summation of the echo voltages shown in FIGS. 4 and 3 takes place, so that the writing pulses a or e supplied to the thermal recorder 14 have different amplitudes.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of the receiving section of the echo sounder. FIG. 2 is a diagram showing the time variation of a transmitted pulse with a transmission duration τ. 3-3 are diagrams of the echo voltages at connection points 3 or 4 or 5 or 6 of the circuit diagram in FIG. 1, respectively. 3.4.5... Connection point, 10... Receiving section, 11...
・Acoustic transducer, 12...Echo amplifier, 1
6. Envelope rectifier, 14. Thermal recording device.

Claims (1)

[Scope of Claims] 1. An echo sounder having a receiving section for receiving ocean floor echoes generated by transmitting sound waves to the ocean floor and recording at least one echo track, the receiving section comprising an acoustic transducer and an acoustic transducer. An echo sounder comprising an echo amplifier, a recording amplifier, a recorder controlled by the recording amplifier, and a threshold circuit for forming a threshold that automatically matches the intensity of the seafloor echo, the acoustic transducer ( 11), the echo amplifier (12) and the threshold circuit (15) are connected in series,
The output side of the recording amplifier is connected to the input side of the recording amplifier, which is configured as an operational amplifier (13), and the output side of the recording amplifier is connected to the recorder (14) via a first diode (19), and the threshold circuit (15) is connected to the input side of the recording amplifier configured as an operational amplifier (13). ) comprises the envelope rectifier (16) and a differential element that connects the output side of the envelope rectifier (16) to the input side of the operational amplifier (13), and the differential element includes a capacitor (17); A resistor (18) connected in parallel to the input side of the operational amplifier (13).
) and a second diode (20) connected in series. 2. The input side of the operational amplifier (13) is connected to the operational amplifier (13).
The echo sounder according to claim 1, which is the non-inverting input side of item 3). 3. A second resistor (21) having a larger resistance value than the first resistor (18) is connected in parallel to the series connection consisting of the resistor (18) and the second diode (20). An echo sounder according to claim 1 or 2. 4. Any one of claims 1 to 3, wherein the operational amplifier (13) has an amplification factor of about 50 times.
The echo sounder described in section. 5. The output side of the envelope rectifier (16) is connected to the output side of the first diode (19) via the third diode (24), and the connection point is connected to the ground via the third resistor (23). An echo sounder according to any one of claims 1 to 4, which is connected to an electric potential.